Air-conditioning vent

ABSTRACT

An air vent for an air-conditioning duct especially suitable for automobiles. The vent has a plurality of movable vanes supported by a barrel which is pivotably mounted within a duct housing. Resilient, self-locking tabs are provided on either side of the duct housing to hold the air vent in a support plate. The tabs abut against the sides of the barrel when it is in the normal operating position, but are free to move inwardly when the barrel is in an inoperative position. The air vent is shipped with the barrel in the inoperative position and, for assembly into the duct, is quickly snapped into place in the support plate. The barrel is then rotated to a normal operating position. Means are provided to retain the barrel in the normal operating position once the assembly has been fixed in the support plate.

United States Patent Mar. 14, 1972 Nieboer [54] AIR-CONDITIONING VENT[72] Inventor: Keith A. Niehoer, Holland, Mich.

[73] Assignee: Keeler Brass Company, Grand Rapids,

Mich.

[22] Filed: Feb. 27, 1970 21 Appl.No.: 15,049

[52] U.S.Cl. ..98/107,29/l57.3R,49/57, 98/110, 98/114 [51] Int.Cl..F24f1l3/00 [58] Field oi Search ..98/107, 110, 114, 40 A, 40 VM;49/57; 70/450; 29/l57.3 R

[56] References Cited UNITED STATES PATENTS 2,229,388 1/1941 Postlewait..98/114 3,012,494 12/1961 Drummond.... ...98/40A 1,336,210 4/1920Druliner ..98/l14 3,031,945 5/1962 Kelly ..98/ll4 3,236,171 2/1966Vaskov ..98/114 Palmer ..98ll l4 Broberg ..98/1 14 [57] ABSTRACT An airvent for an air-conditioning duct especially suitable for automobiles.The vent has a plurality of movable vanes supported by a barrel which ispivotably mounted within a duct housing. Resilient, self-locking tabsare provided on either side of the duct housing to hold the air vent ina support plate. The tabs abut against the sides of the barrel when itis in the normal operating position, but are free to move inwardly whenthe barrel is in an inoperative position, The air vent is shipped withthe barrel in the inoperative position and, for assembly into the duct,is quickly snapped into place in the support plate. The barrel is thenrotated to a normal operating position. Means are provided to retain thebarrel in the normal operating position once the assembly has been fixedin the support plate,

24 Claims, 6 Drawing Figures mmmdl March M, W72 3,648,592

INVENTOR KEITH A [0155092 ATTORNEYS AIR-CONDITIONING VENT BACKGROUND OFTHE INVENTION In air-conditioning units and in particular those mountedin automobiles, conventional practice provides an air vent mounted on asupport plate which, once mounted, must be locked into position so as tobe incapable of being pulled away from the support plate. Priorconstructions have been beset with the problem of locking means whichare complicated and expensive to manufacture, and which are notconducive to quick assembly. Even the use of an inexpensive lockingscrew does not avoid the time-consuming work required to screw in suchlocking screws.

SUMMARY OF THE INVENTION This invention relates to air vents. In one ofits aspects, it relates to a method for locking an assembled air vent toa supporting plate. In another of its aspects, the invention relates toan improvement in air vents of the type which include a housing, and abarrel pivoted within the housing and provided with means forcontrolling air flow through the housing. The improved air vent hasmeans for attaching the housing to a support plate, the means beingmounted on the housing of the air vent so as to be locked in engagementwith the support plate when the barrel of the air vent is in itsoperative controlling positions, and so as to be free for movement intoand out of engagement with the support plate when the barrel is ininoperative positions, i.e., other than the normal operating positions.This is accomplished by providing means for blocking the attaching meansfrom disengagement with the plate and means for preventing the blockingmeans from moving out of its blocking position. The blocking meansincludes the barrel.

By means of the aforedescribed structure, a method of shipping andassembly of the air vent is provided wherein the barrel is shipped whiletemporarily restrained in inoperative positions. The assembly of the airunit occurs thereafter by sliding the air vent into the support platewith the barrel still temporarily restrained in the inoperativeposition. After the air vent housing is positioned with its outerflanges in abutment with the support plate, the locking meansautomatically snaps behind the support plate so as to permanently engagethe support plate. Thereafter, the barrel is moved to its operativecontrolling positions whereby it prevents the locking means fromunlocking the air vent housing from the support plate. Means are alsoprovided to prevent the barrel from moving back into its inoperativeposition, thereby per manently preventing any unlocking.

Accordingly, it is an object of the invention to provide an air ventunit having a locking means of simple inexpensive construction whichallows the vent to be easily assembled with the support plate.

It is another object of the invention to provide a facile method ofshipping and assembly of an air vent unit for automobiles and the like.

It is a further object of the invention to provide an air vent unit anda method of assembling the unit into an air duct wherein, once the ventunit is assembled, the barrel of the unit is restrained from movement toan inoperative position.

It is an object of this invention to provide an air vent for automobileair-conditioning systems and the like wherein the air vent can besnapped into place in the automobile air system as a final assemblystep, and then, by a simple rotation of an air directing barrel of theair vent, the air vent is locked in place in the automobile air system.

Other objects and advantages will become apparent upon reference to thefollowing drawings and detailed discussion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan viewillustrating an air vent constructed in accordance with the inventionand positioned and locked to the supporting plate;

FIG. 2 is a fragmentary sectional view, partially broken away, takenalong the lines II-II of FIG. I;

FIG. 3 is a fragmentary sectional view taken along the lines IIIIIl ofFIG. 2, the louvers'of the barrel being omitted for clarity;

FIG. 4 is a sectional view similar to FIG. 3, but illustrating the airvent in its unlocked position;

FIG. 5 is a fragmentary sectional view taken along the lines V-V ofFIG.3; and

FIG. 6 is a fragmentary sectional view taken along the lines VI-VI ofFIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, there isillustrated an air vent which is mounted on the dash of an automobile,for example, by means such as a supporting plate 10. The air vent has abarrel 12 with exterior surfaces 13 (FIG. 3) and stub axles 16 (FIG. 2)by which the barrel is pivotably mounted within a housing 14. A louveredstructure I8 is provided within the barrel 12 (FIGS. 1 and 2), tocontrol the flow of air through the air vent, including closing off theflow. The structure 18 comprises individual louvers I9 and 22 eachpivotally mounted to the inside walls of the barrel 12. The louvers I9and 22 are joined by a linkage 20 at a top corner of each louver. Abutton 2I, mounted on the face of barrel I2, engages the cent-er louver22 such that movement of the center louver 22 causes the louver 22 topivot about its axes within the barrel 12. Because all louvers arejoined by linkage 20, rotation of louver 22 will cause all louvers topivot about their respective axes. In this manner, the flow of air canbe directed either straight out or deflected to either side of the vent.It should be noted that any louvered structure, adjustable or otherwise,controlling the air flow through the air vent when the barrel I2 is incertain operative positions can be utilized. An example of anotherusable type is disclosed in US. Pat. No. 3,456,574.

At the outer end 23 of the housing, a circumferential flange 24 extendsaround the opening in plate 10. A felt strip 82 can be provided betweenflange 24 and plate 10 to dampen the vibrational noises between the twoparts.

In accordance with the invention, the housing I4 is provided at oppositesides with locking abutments or tabs 30 having camming surfaces 31 (FIG.4). The tabs are integrally formed with sides 32 and 34 of the housing14. The housing is made from a resilient material such as plastic sothat the tabs 30 can flex resiliently with respect to the sides 34 and36. The walls of the sides 32 and 34 are substantially inflexible due totheir construction and the ends 38 of the tabs 30 opposite the hinges 36are also inflexible due to their increased thickness. The thickness ofthe ends 38 exceeds that of the walls of the sides 32 and 34. Each ofthe tabs 30 bends at hinges 36. The housing is preferably molded in onepiece out of plastic so that the tabs 30 are formed integrally with thesides 32 and 34, with a slot 40 (FIG. 2) around three sides of the tab30. Any suitable plastic material can be utilized. For example, thematerial can be ABS plastic (acrylonitrile-butadiene-styrene),polyethylene, polypropylene, polyvinyl chloride, or other syntheticpolymers. 7

The barrel I2 is shaped so that the top and bottom edges are closelyadjacent to the tabs 30 when the barrel is oriented in its normaloperative position. Thus, as seen in FIG. 3, the operative orientationof the barrel 12 allowing the barrel to control the flow of air by thelouvers I9 through the air vent, also prevents the tabs 30 from beingdepressed below the exterior surface of the walls forming the sides 32and 34. On the other hand, when the barrel 12 is rotated into itsinoperative position (FIG. 4), there is ample room for the tabs 30 to bedepressed below the exterior surface of the sides 32 and 34.

A stop 50 is mounted on side 52 of the housing to control and restrainthe amount of rotation which the barrel 12 can undergo, the stopcomprising a shoulder which extends at least into the path of rotationof the barrel 12 (FIG. 4). Specifically, the surface 54 of the shoulder50 abuts against surface 56 of the barrel I2 when the barrel is rotatedclockwise from the position shown in solid lines in FIG. 3 to theposition shown in phantom in that figure. At that point, the barrel 12can undergo no further clockwise rotation. Thus, the surface 54 servesto limit the rotation of the barrel 12 in its operative controllingposition to a point where the exterior surface 13 of the barrel forms anangle alpha with respect to the flange 24. A preferred value for alpha"is 35.

A raised surface 58 is provided on the shoulder 50 as a stop for atongue 60 which depends from the barrel 12. This stops rotation when thebarrel is rotated in a counterclockwise direction (FIG. 3). In thismanner the other limit of rotation for the barrel 12 is established foroperative conditions. The edge 62 of the tongue 60 is blunted so as topreclude the tongue from being forced over the shoulder 50 at thesurface 58 thereof. The barrel l2 rotated to its limit in one directionwith respect to the housing is shown in solid lines in FIG. 3. Thus, thesurface 13 of the barrel 12 can tilt from the plane of the flange 24 upto angle beta. The tongue 60 can be shaped so that the angle beta isequal to the angle alpha.

The air vent is preferably assembled with the barrel 12 in the positionshown in FIG. 4. In order that the barrel be rotatable to the operativepositions shown in FIG. 3, a camming surface 70 is formed on the end ofthe shoulder 50 (FIGS. 4 and 5). The surface is sloped toward the side32 and upwardly toward flange 24, so as to assist in the camming of thetongue 60 thereover when moving from the position shown in FIG. 4 to theposition shown in FIG. 3. A surface 72 is formed on the tongue 60 (FIGS.3 and 6) to slope downwardly and inwardly approximately in the sameplane as that of surface 70. It will be readily appreciated that thecooperating surfaces 70 and 72 allow the tongue 60 to ride over theshoulder 50 but only when rotating in the clockwise direction from theposition shown in FIG. 4 to that shown in FIG. 3.

METHOD Because of the clearanceprovided for the tab 30 when the barrelis in its inoperative position as shown in FIG. 4, the barrel 12 isassembled to the housing 14 so that it occupies the position shown inFIG. 4. The shoulder 50 serves to temporari ly restrain the barrel inthis position by slightly abutting the tongue 60 notwithstanding thecooperating surfaces 70 and 72. The surface 58 of the shoulder alsoprevents additional counterclockwise rotation from the position shown inFIG. 4 by abutting against the surface 76 of the barrel 12.

While the barrel 12 is so oriented, the air vent housing is assembledinto the support plate by sliding the end 80 opposite to the end bearingthe flanges 22 into the opening in the support plate. As the housing 14slides into the opening, the edges of the plate 10 bear against thecamming surfaces 31 to force tabs 30 inwardly below the exterior surfaceof the walls 32 and 34. The tabs 30 continue to flex inwardly until theyoccupy the positions shown in phantom in FIG. 4, at which position theplate 10 slides up over the tabs and into abutment with the flanges 22.A compressible felt strip 82 is attached to the underside of the flanges22 so as to deaden any rattle which might develop otherwise.

After the plate has slipped over the tabs into the position abutting theflanges 22, the hinges 36 automatically force the tabs 30 outwardly intothe released position shown in FIG. 3, thereby snapping behind theunderside of the plate 10. The housing is thus secured to the plate 10with the plate between the tabs 30 and the flanges 22.

The barrel 12 is then rotated in the direction of the arrow 84 as shownin FIG. 4 until the surface 72 of tongue 60 cams up over the surface 70of the shoulder 50. The tongue 60 is thereby carried over the shoulder50 into its locked arrangement as shown in FIG. 3. The ends of barrel 12are thus in a position to prevent the tabs 30 from being depressed awayfrom their engagement with the plate 10. The edge 62 of the tongue 60and the surface 56 of the barrel 12 thereafter prevent the barrel fromrotating out of its operative controlling positions and serve to limitthe motion of the surface 13 of the barrel to the angular limitationsdefined by angles "alpha" and beta.

It will be appreciated that this assembly of the vent housing to theplate 10 is exceedingly rapid, the camming surfaces 31 on the abutments30 allowing the assembly to be accomplished merely by pushing thehousing 12 into the opening. A simple turning of the barrel 12 completesthe assembly so as to both lock the vent housing 12 in its position inengagement with the support plate 10 and also so as to limit therotation of the barrel 12 only to its operative air-controllingpositions.

Although the invention has been described in connection with a preferredembodiment, it will be readily appreciated that equivalent structure canbe devised to practice the invention. For example, the angles alpha" andbeta" need not equal 35 but can equal any angle which still allows thebarrel 12 to deliver a flow of air through the vent. Similarly, theangle beta need not be equal to angle alpha." Also, the vent need not belimited to use on automobiles. Thus, the invention is intended toinclude these equivalent embodiments unless the following claims bytheir express language state otherwise.

The embodiments of the invention is which an exclusive property orprivilege is claimed are defined as follows.

1. In an air-conditioning vent including a housing, and a bar relpivotably mounted within said housing and provided with means forcontrolling air flow through said housing, the improvement comprisingsaid housing including means for attaching said housing to a supportplate, said attaching means being mounted on said housing so as to belocked in engagement with said plate and prevented from disengagement bysaid barrel when said barrel is in its operative controlling positions,and so as to be free for movement into or out of engagement with saidplate when said barrel is in inoperative positions other than saidcontrolling positions.

2. The improved vent as defined in claim 1, wherein said attaching meansincludes abutments resiliently mounted on opposite sides of saidhousing, said barrel having edges sufficiently close to said housingsides as to prevent inward movement of said abutments when said barrelis in said controlling positions.

3. The improved vent as defined in claim 2, wherein said housingopposite sides are parallel to the pivot axis of said barre].

4. The improved vent as defined in claim 2, wherein said abutments aretabs integrally formed with said housing opposite sides, a space beingformed between said tabs on at least three sides thereof forming ahinge, the thickness of said tabs at the free end thereof exceeding thethickness of the walls of said housing.

5. The improved vent as defined in claim 4, wherein the thickness ofsaid tabs decreases progressively from said end to said hinge, at whichsaid tab thickness equals that of said walls.

6. The improved vent as defined in claim 4 further including a flangeextending from said housing at one end thereof, said free end of saidtabs being positioned between said flange and said hinge.

7. The improved vent as defined in claim 4, wherein said housing andsaid tabs are integrally molded out of a resilient plastic.

8. The improved vent as defined in claim 1, and further including stopmeans for preventing said barrel from moving from said controllingpositions into one of said inoperative,

positions.

9. The improved vent as defined in claim 8, wherein said stop meansincludes means for temporarily retaining said barrel in said inoperativepositions, and said housing can be mounted on said support plate by saidmovement of said attaching means while said barrel is still retained insaid inoperative positions.

10. The improved vent as defined in claim 9, wherein said stop meansincludes a shoulder on said housing projecting into the line ofrotational travel of said barrel, regardless of the position of saidbarrel, so as to restrict the rotational move ment of said barrel eithertemporarily to said inoperative positions, or permanently to saidcontrolling positions.

11. The improved vent as defined in claim 10, wherein said stop meansincludes an abutment on said barrel, said abutinnm-v "Hm ment having acamming surface, said camming surface being sloped and positioned so asto cam said abutment over said shoulder when said barrel is rotated onlyin one rotational direction.

12. The improved vent as defined in claim 11, wherein said cammingsurface is located on a tongue projecting outwardly away from saidbarrel.

13. The improved vent as defined in claim 111, wherein said shoulder iscooperatively sloped so as to assist said abutment to cam over saidshoulder but only when said barrel is rotated in said one rotationaldirection.

114. In an air-conditioning vent including a housing, and a barrelpivoted within said housing between at least operative controlling andinoperative positions, said barrel including an abutment and providedwith means for controlling air flow through said housing, theimprovement comprising said housing including at least one stoppositioned adjacent the end of said barrel so as to abut said abutmentpositioned on the end of said barrel, said stop and abutment includingcamming means, said stop providing a means for restraining the rotationof said barrel by means of said abutment in said inoperative positionuntil said barrel is rotated, said rotation causing said abutment to becammed over said stop by said camming means, thereby placing said barrelin at least one of said operative controlling positions.

15. The improved vent as defined in claim 14, wherein said stop includesa shoulder on at least one side of said housing adjacent to the end ofsaid barrel and projecting into the line of rotational travel of saidabutment positioned on the end of said barrel. I

16. The improved vent as defined in claim 15, wherein said barrelincludes a tongue projecting therefrom, said tongue and said shoulderabutting to prevent movement of said barrel in one rotational directionbeyond its operative controlling positions, said barrel having meanscontacting said shoulder to restrain movement of said barrel in theopposite rotational direction beyond its operative controllingpositions.

17. In an air vent mountable on a support, said vent including ahousing, means for directing flow out through the vent, and resilientlocking means for attaching said vent to a support plate, theimprovement comprising means for blocking said locking means fromdisengagement from said plate, said blocking means consisting of saidflow directing means movable from a blocking position to a non-blockingposition, and means for preventing said blocking means from moving fromthe blocking position, which preventing means include a stop integralwith said housing and an abutment formed integrally with said flowdirecting means.

18. In an air vent mountable on a support, said vent including ahousing, means for directing flow out through the vent, and means forattaching said vent to a support plate, the improvement comprising meansfor blocking said attaching means from disengagement from said plate,said blocking means consisting of said flow directing means, and meansfor preventing said blocking means from moving from the blockingposition, which preventing means are attached to said flow directingmeans, said attaching means including tabs hingedly attached formovement into and out of said housing.

19. The improved vent as defined in claim 18, wherein said blockingmeans comprises a barrel-like cylinder rotatably mounted so as to blocksaid tabs from moving into the housing when in one position, and so asto allow movement of said tabs into said housing when in anotherposition.

20. The improved vent as defined in claim 19, wherein said preventingmeans includes a shoulder fixed to said housing within the rotationalpath of said cylinder.

21. The improved vent as defined in claim 18, wherein said tabs includemeans for camming the same into said housing when the latter is insertedinto the support.

22. A method of assembling an air vent in a support plate of anair-conditioning system, said vent including a housing, a barrelprovided with means for controlling air flow through said housing, saidhousing includin clipping abutments resiliently connected to the wallsof Set housing in the vicinity of said barrel, when mounted, forengaging said support plate, means for locking said barrel in a positionoperative to control the air flow, the surfaces of said barrel in saidoperative position being so close to said abutments as to prevent themfrom disengaging said plate, and means for biasing said abutmentsoutwardly away from said barrel; the method comprising the steps of (a)assembling said barrel to said housing so that it is in a positiontherein other than said operative position capable of controlling theair flow, said locking means being disengaged; and (b) shipping saidvent with said barrel temporarily limited to said other position withsaid locking means disengaged.

23. The method as defined in claim 22, and further including the stepsof slidingsaid vent with respect to said plate while retaining saidbarrel in said other position, so that said plate slides over said wallsand said abutments, said abutments snapping behind said plate to locksaid housing to said support plate, and whereby said abutments can nolonger be depressed and said vent is locked to said plate permanently.

24. A method of mounting within a support plate an air vent including ahousing, a barrel provided with means for controlling air flow throughsaid housing, said housing including clipping abutments resilientlyconnected to the walls of said housing in the vicinity of said barrel,when mounted, for engaging said support plate, means for locking saidbarrel in a position operative to control the air flow, the surfaces ofsaid barrel in said operative position being so close to said abutmentsas to prevent them from disengaging said plate, and means for biasingsaid abutments outwardly away from said barrel; the method comprisingthe steps of rotating said barrel from an inoperative position to saidoperative positions and thereafter preventing said barrel from rotatingback into said other position, whereby said abutments can no longer bedepressed.

1. In an air-conditioning vent including a housing, and a barrelpivotably mounted within said housing and provided with means forcontrolling air flow through said housing, the improvement comprisingsaid housing including means for attaching said housing to a supportplate, said attaching means being mounted on said housing so as to belocked in engagement with said plate and prevented from disengagement bysaid barrel when said barrel is in its operative controlling positions,and so as to be free for movement into or out of engagement with saidplate when said barrel is in inoperative positions other than saidcontrolling positions.
 2. The improved vent as defined in claim 1,wherein said attaching means includes abutments resiliently mounted onopposite sides of said housinG, said barrel having edges sufficientlyclose to said housing sides as to prevent inward movement of saidabutments when said barrel is in said controlling positions.
 3. Theimproved vent as defined in claim 2, wherein said housing opposite sidesare parallel to the pivot axis of said barrel.
 4. The improved vent asdefined in claim 2, wherein said abutments are tabs integrally formedwith said housing opposite sides, a space being formed between said tabson at least three sides thereof forming a hinge, the thickness of saidtabs at the free end thereof exceeding the thickness of the walls ofsaid housing.
 5. The improved vent as defined in claim 4, wherein thethickness of said tabs decreases progressively from said end to saidhinge, at which said tab thickness equals that of said walls.
 6. Theimproved vent as defined in claim 4 further including a flange extendingfrom said housing at one end thereof, said free end of said tabs beingpositioned between said flange and said hinge.
 7. The improved vent asdefined in claim 4, wherein said housing and said tabs are integrallymolded out of a resilient plastic.
 8. The improved vent as defined inclaim 1, and further including stop means for preventing said barrelfrom moving from said controlling positions into one of said inoperativepositions.
 9. The improved vent as defined in claim 8, wherein said stopmeans includes means for temporarily retaining said barrel in saidinoperative positions, and said housing can be mounted on said supportplate by said movement of said attaching means while said barrel isstill retained in said inoperative positions.
 10. The improved vent asdefined in claim 9, wherein said stop means includes a shoulder on saidhousing projecting into the line of rotational travel of said barrel,regardless of the position of said barrel, so as to restrict therotational movement of said barrel either temporarily to saidinoperative positions, or permanently to said controlling positions. 11.The improved vent as defined in claim 10, wherein said stop meansincludes an abutment on said barrel, said abutment having a cammingsurface, said camming surface being sloped and positioned so as to camsaid abutment over said shoulder when said barrel is rotated only in onerotational direction.
 12. The improved vent as defined in claim 11,wherein said camming surface is located on a tongue projecting outwardlyaway from said barrel.
 13. The improved vent as defined in claim 11,wherein said shoulder is cooperatively sloped so as to assist saidabutment to cam over said shoulder but only when said barrel is rotatedin said one rotational direction.
 14. In an air-conditioning ventincluding a housing, and a barrel pivoted within said housing between atleast operative controlling and inoperative positions, said barrelincluding an abutment and provided with means for controlling air flowthrough said housing, the improvement comprising said housing includingat least one stop positioned adjacent the end of said barrel so as toabut said abutment positioned on the end of said barrel, said stop andabutment including camming means, said stop providing a means forrestraining the rotation of said barrel by means of said abutment insaid inoperative position until said barrel is rotated, said rotationcausing said abutment to be cammed over said stop by said camming means,thereby placing said barrel in at least one of said operativecontrolling positions.
 15. The improved vent as defined in claim 14,wherein said stop includes a shoulder on at least one side of saidhousing adjacent to the end of said barrel and projecting into the lineof rotational travel of said abutment positioned on the end of saidbarrel.
 16. The improved vent as defined in claim 15, wherein saidbarrel includes a tongue projecting therefrom, said tongue and saidshoulder abutting to prevent movement of said barrel in one rotationaldirection beyond its operative controlling positions, said barRel havingmeans contacting said shoulder to restrain movement of said barrel inthe opposite rotational direction beyond its operative controllingpositions.
 17. In an air vent mountable on a support, said ventincluding a housing, means for directing flow out through the vent, andresilient locking means for attaching said vent to a support plate, theimprovement comprising means for blocking said locking means fromdisengagement from said plate, said blocking means consisting of saidflow directing means movable from a blocking position to a non-blockingposition, and means for preventing said blocking means from moving fromthe blocking position, which preventing means include a stop integralwith said housing and an abutment formed integrally with said flowdirecting means.
 18. In an air vent mountable on a support, said ventincluding a housing, means for directing flow out through the vent, andmeans for attaching said vent to a support plate, the improvementcomprising means for blocking said attaching means from disengagementfrom said plate, said blocking means consisting of said flow directingmeans, and means for preventing said blocking means from moving from theblocking position, which preventing means are attached to said flowdirecting means, said attaching means including tabs hingedly attachedfor movement into and out of said housing.
 19. The improved vent asdefined in claim 18, wherein said blocking means comprises a barrel-likecylinder rotatably mounted so as to block said tabs from moving into thehousing when in one position, and so as to allow movement of said tabsinto said housing when in another position.
 20. The improved vent asdefined in claim 19, wherein said preventing means includes a shoulderfixed to said housing within the rotational path of said cylinder. 21.The improved vent as defined in claim 18, wherein said tabs includemeans for camming the same into said housing when the latter is insertedinto the support.
 22. A method of assembling an air vent in a supportplate of an air-conditioning system, said vent including a housing, abarrel provided with means for controlling air flow through saidhousing, said housing including clipping abutments resiliently connectedto the walls of said housing in the vicinity of said barrel, whenmounted, for engaging said support plate, means for locking said barrelin a position operative to control the air flow, the surfaces of saidbarrel in said operative position being so close to said abutments as toprevent them from disengaging said plate, and means for biasing saidabutments outwardly away from said barrel; the method comprising thesteps of (a) assembling said barrel to said housing so that it is in aposition therein other than said operative position capable ofcontrolling the air flow, said locking means being disengaged; and (b)shipping said vent with said barrel temporarily limited to said otherposition with said locking means disengaged.
 23. The method as definedin claim 22, and further including the steps of sliding said vent withrespect to said plate while retaining said barrel in said otherposition, so that said plate slides over said walls and said abutments,said abutments snapping behind said plate to lock said housing to saidsupport plate, and whereby said abutments can no longer be depressed andsaid vent is locked to said plate permanently.
 24. A method of mountingwithin a support plate an air vent including a housing, a barrelprovided with means for controlling air flow through said housing, saidhousing including clipping abutments resiliently connected to the wallsof said housing in the vicinity of said barrel, when mounted, forengaging said support plate, means for locking said barrel in a positionoperative to control the air flow, the surfaces of said barrel in saidoperative position being so close to said abutments as to prevent themfrom disengaging said plate, and means for biasing said abutmentsoutwardly away from said barrel; the method comprising the steps ofrotating said barrel from an inoperative position to said operativepositions and thereafter preventing said barrel from rotating back intosaid other position, whereby said abutments can no longer be depressed.